Date:   Mon, 24 Jul 2017 20:32:01 +0200
From:   Jerome Brunet <jbrunet@...libre.com>
To:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Cc:     Neil Armstrong <narmstrong@...libre.com>,
        Joseph Kogut <joseph.kogut@...il.com>,
        Kevin Hilman <khilman@...libre.com>, mark.rutland@....com,
        devicetree@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        robh+dt@...nel.org, carlo@...one.org,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] ARM64: meson-gxl: disable broken eee

On Mon, 2017-07-24 at 20:20 +0200, Martin Blumenstingl wrote:
> On Mon, Jul 24, 2017 at 6:09 PM, Jerome Brunet <jbrunet@...libre.com> wrote:
> > On Mon, 2017-07-24 at 14:26 +0200, Neil Armstrong wrote:
> > > On 07/24/2017 02:06 PM, Neil Armstrong wrote:
> > > > On 07/23/2017 07:03 PM, Joseph Kogut wrote:
> > > > > Hi Kevin,
> > > > > 
> > > > > I tested on a P212 reference board, which is currently the only GXL
> > > > > based board I have.
> > > > > 
> > > > > Before applying the patch, high activity on the ethernet interface
> > > > > would cause the link to break, requiring the interface to be brought
> > > > > down and back up before it would work again. After applying the patch,
> > > > > I could not get the link to break with any transfers.
> > > > > 
> > > > > _______________________________________________
> > > > > linux-arm-kernel mailing list
> > > > > linux-arm-kernel@...ts.infradead.org
> > > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> > > > > 
> > > > 
> > > > Hi Joseph,
> > > > 
> > > > [please keep the history of the conversation when replying]
> > > > 
> > > > Is it a original P212 board, or a board based on the P212 ref design ?
> > > > 
> > > > I'm currently testing the v4.13-rc2 on the official P212 board we
> > > > received
> > > > from Amlogic
> > > > and using iperf3 in both directions, I have an issue after a few minutes
> > > > running iperf3 with :
> > > > 
> > > > # while true ; do iperf3 -c 192.168.1.21 ; iperf3 -c 192.168.1.21 -R ;
> > > > done
> > > > 
> > > > That cycles between the two iperf directions.
> > > > 
> > > > After a few minutes, it stalls with :
> > > > 
> > > > Connecting to host 192.168.1.21, port 5201
> > > > [  4] local 192.168.1.183 port 51286 connected to 192.168.1.21 port 5201
> > > > [ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
> > > > [  4]   0.00-1.00   sec  1.64 MBytes  13.7 Mbits/sec    2   1.41 KBytes
> > > > [  4]   1.00-2.00   sec  0.00 Bytes  0.00 bits/sec    1   1.41 KBytes
> > > > [  4]   2.00-3.00   sec  0.00 Bytes  0.00 bits/sec    0   1.41 KBytes
> > > > [  4]   3.00-4.00   sec  0.00 Bytes  0.00 bits/sec    1   1.41 KBytes
> > > > [  4]   4.00-5.00   sec  0.00 Bytes  0.00 bits/sec    0   1.41 KBytes
> > > > [  4]   5.00-6.00   sec  0.00 Bytes  0.00 bits/sec    0   1.41 KBytes
> > > > [  4]   6.00-7.00   sec  0.00 Bytes  0.00 bits/sec    1   1.41 KBytes
> > > > [  4]   7.00-8.00   sec  0.00 Bytes  0.00 bits/sec    0   1.41 KBytes
> > > > [  4]   8.00-9.00   sec  0.00 Bytes  0.00 bits/sec    0   1.41 KBytes
> > > > 
> > 
> > Same kind of test shows no issue on the libretech-cc and the khadas-vim
> > In this case, I don't think meson-gxl.dtsi is where you should make your
> > change.

ahahah, silly me ! I forgot that it was 100MBps PHY.
tx delay makes no sense here, 2ns delay would not make much difference on a
25MHz clock

Sorry for the confusion


> > 
> > > > 
> > > > And then, after:
> > > > # ifconfig eth0 down
> > > > # ifconfig eth0 up
> > > > 
> > > > It cycles between :
> > > > [ 1483.009919] meson8b-dwmac c9410000.ethernet eth0: Link is Up -
> > > > 100Mbps/Full - flow control rx/tx
> > > > [ 1487.105725] meson8b-dwmac c9410000.ethernet eth0: Link is Down
> > > > [ 1490.177943] meson8b-dwmac c9410000.ethernet eth0: Link is Up -
> > > > 100Mbps/Full - flow control rx/tx
> > > > [ 1494.273713] meson8b-dwmac c9410000.ethernet eth0: Link is Down
> > 
> > This does not look like the issue we had on the odroid-c2.
> > However, I have seen behavior like this (link down/up flickering) when the
> > rgmii
> >  delays are way off.
> > 
> > Maybe you could try playing with "amlogic,tx-delay-ns" property ?
> 
> we need to change dwmac-meson8b.c so it applies the TX delay also for
> RMII PHYs. currently the TX delay is always set to 0 for RMII PHYs,
> see: [0]
> 
> > > > 
> > > > and so on.
> > > > 
> > > > And this patch does not fix this at all.
> > > > 
> > > > It seems to be more a PHY driver issue here.
> > > > 
> > > > Could you share the results with the same command ?
> > > > 
> > > > Neil
> > > > 
> > > 
> > > I forgot to precise, this issue occurs when the "GXL PHY driver" is
> > > disabled,
> > > only relying on the
> > > Generic PHY Driver.
> > > 
> > > [  630.767538] Generic PHY 0.e40908ff:08: attached PHY driver [Generic
> > > PHY]
> > > (mii_bus:phy_addr=0.e40908ff:08, irq=-1)
> > > 
> > > 
> > > When the PHY driver is loaded the issue disappears, with and without your
> > > patch.
> > > 
> > > [   25.355620] Meson GXL Internal PHY 0.e40908ff:08: attached PHY driver
> > > [Meson GXL Internal PHY] (mii_bus:phy_addr=0.e40908ff:08, irq=-1)
> > > 
> > > Could you please check the PHY Driver is loaded ?
> > > 
> > > Thanks,
> > > Neil
> > 
> > 
> > _______________________________________________
> > linux-amlogic mailing list
> > linux-amlogic@...ts.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-amlogic
> 
> 
> [0] https://github.com/torvalds/linux/blob/master/drivers/net/ethernet/stmicro
> /stmmac/dwmac-meson8b.c#L222

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